LeBron James identified defense as the main reason for the two-time defending champions' sluggish 4-3 start.

"It's simple. These first seven games, we're playing like s--- defensively," James said, according to ESPN.com. "It's that simple. We're not a sugarcoat team. We came in and got right down to it. We're terrible on defense, and we've got to change that."

The Heat entered Tuesday's game against Milwaukee ranked 25th in points allowed per possession, according to ESPN.com's figures, and 27th based on Basketball-Reference's defensive efficiency calculations. Miami is also 26th in field-goal defense (47.3 percent) and 21st in points allowed (100.9). Those numbers help explain why the Heat are only a game above .500 despite leading the NBA in offensive efficiency.